Fuel pump for multicylinder internal-combustion engines



April 1, 1930. J. MAHLER 'PUMP MULTICYLINDER INTERNAL COMBUSTION ENGINES Filed April 11, 1925 Patented Apr. 1, 1930 UNITED STATES PATENT OFFICE 'Jormim MAHLER, or AUGSBURG, GERMANY, AssIenon TO THE Finn: mascmn'mr- FABRIK AUGSBURG-NUERNBERG, AKT'IENGESELLSCHAFT, or AUGSBURG, enn- MANY, A CORPORATION OF GERMANY FUEL PUMP Fen MULTICYLINDER In'rErmAL-coMBUs'rIon ENGINES lpplication filed April 11, 1925, Serial No. 22,374, and 'in Germany May 10, 1924.

that a portion oft-he fuel escaping through the relief valve, returns to the suction chamber. This results in the drawback that if the check. valve mounted in one-of the injection pipes becomes leaky or sticks, the compression or explosion pressure can. pass from the cylinder into the pump, through the open relief valve into the relief chamber, and from the latter into the suction chamber, from the.

moment when. the relief valve belonging-to the said pipe is opened and the fuel delivery.

in this pipe interrupted. Further, the pumps of the other cylinders, connected to the suction chamber in question, are also placed out of action as the excess of pressure in the suction-chamber stops the supply of fuel. from the storage tank.

This drawback is avoided according to the invention by providing onecommon relief chamber for all the relief valves, which chamber is completely separated from the suction chamber. This common chamber is connected in a manner well known in' itself to the fuel storage tank. When the above mentioned contingency occurs, namely when the check valve .in one injection pipe becomes leaky or sticks, the high cylinder pressure passing through the said in ection pipe into the relief chamber, cannot pass into the com mon suction chamber of the fuel pump units and place the fuel pump units out of action closed the nature of my said invention and performed,-

0 by throttling the fuel flow. On the contrary it will expand in the fuel storage tank which can be freed from excess pressure in any suit-' able manner, for instance by means of a valve mounted in the cover. 'Thus, the tank functions as a pressure chamber or dome to receive the excess pressure and permit its esca e to the atmosphere without objectionably a ecting the fuel supply, or'the operation of the other pump units.

In order that the said invention may be clearly understood and readily carried into eflect,'the same will now be described more fully with reference to the accompanying drawing, in which Fig. l is a vertical sectional viewthrough a fuel feeding device constructed in accord-.

vidual cylinders, each constituted by a plung-.

er a, a. pressure chamber 6 and a suction valve 0, are mounted in a common casing d and connected in the usual manner to a common suction chamber e which is connected to the storage tank f by means of a supply pipe 9. An injection pipe h leads from the pressure chamber of each pump unit to the corresponding engine cylinder. The reference letter 71 indicates the relief .valves of the pump units, which control relief passages to effect the delivery regulation, the relief passages opening into a common relief chamber 7'. From the lattera return pipe 70 leads to the fuel tank 7. If the check valve (not shown) in one of the injection pipes 72. should become leaky, then, as soon as the fuel delivery of this pipe is interrupted by the opening of the relief valve 2', the explosion pressure that passes from the cylinder into the pump through the open relief valve '71 can pass into the relief chamber j and from here escape to the atmosphere through the pipe is and the fuel tank f. The passage of pressure into the suction chamber 6 which wouldinterrupt the delivery of fuel from the tank f and render all the fuel pump units inoperative, is therefore prevented by this invention.

Having now particularly described and iii-what manner the same to be I declare that what I claim is 1. A fuel feeding device for a multi-cylinder. internal combustion engine of the character described/comprisinga unitary fuel pump structure having a plurality of pump units therein for pumping fuel. to said cylinders, injection pipes connecting said pump units to said several engine cylinders, a fuel supply tank having provisions for relieving excess pressure therein, a common suction chamber formed in said unitary pump structure for supplying fuel to said pump units, a fuel conduit connecting said supply tank with said common suction chamber, a relief passage for each said injection pipe, a common relief chamber formed in said unitary pump structure in communication with said relief passages but closed from direct communication with said common suction chamber, and a conduit opening at one end into the interior of said common relief chamber and opening at the other end into the interior of said fuel supply tank above the normal r liquid level therein.

2. A fuel feeding device for a multi-cylinder internal combustion engine of the character described, comprising a unitary fuel pump structure having a plurality of pump units therein for pumping fuel to said cylinders, injection pipes connecting said pump units to said several engine cylinders, said unitary pump structure having a common suc- I tion chamber formed therein for supplying fuel to said pump units, a source of supply of fuel, a fuel supply passage connecting said source of supply with said common suction chamber, a relief passage for each said in-' jection pipe, an engine operated relief valve for each relief passage for controlling the degree of fuel admission through its associated injection pipe, said unitary pump structure having a common relief chamber therein in communication'with said relief passages but closed from said common suction chamber, and a fuel passage for returning fuel from said com'mon relief chamber to said source of supply of fuel, said relief chamber, return means and source of supply having provisions for relieving excess pressure communicated thereto from any injection pipe through its corresponding relief passage Without disturbing the feed of fuel to said common suction chamber and through said other injection pipes.

3. A multi-cylinder fuel pump of the. character described comprising a unitary" pump block structure, a plurality of pump units within said structure for pumping fuel to the respective cylinders, injection pipes for connecting said several pump units with the respective cylinders, said unitary pump structure having a common suction chamber formed therein for supplying fuel to said plurality of pump units, a relief passage for each said injection pipe, said unitary pump structure also having a common relief chamber formed therein in communication with each of said relief passages, said commonrelief chamber being closed from direct communication with said common suction chamber.

In testimony whereof have aflixed my signature.

JOHANN MAHI muasso 

